Water and air should also be consid

Water and air should also be considered as essential materials. Without adequate moisture, the microbial activity will be limited. Without oxygen, microbial activity will continue, but the type of microbes and the end products are generally not considered desirable. A general recommendation is to avoid materials that have been piled and rotted without adequate oxygen. These materials will usually have a foul odor or stench of decay. The bacteria that form when materials decay without adequate oxygen usually creates products in the compost that are not desirable.